Workpiece sensor and tape cutoff for sewing machines

ABSTRACT

The present machine is for affixing binding tapes to articles and including attachments for such machines which allow the machine to be run either manually or automatically. In the automatic position of the attachments, they start the machine, upon presentation of a workpiece to the machine, cut the tape at the start and finish of the work through a piston driven sheartype cutter having a driven blade cooperating with a fixed bar supporting the tape and stop the machine automatically. Also the operator can run the machine manually and stop the machine at any time when running the machine in said automatic position of the attachments.

United States Inventors Appl. No.

Filed Patented Assignee atent Roy E. Miller Mechanicsburg; Robert F. Miller. Camp Hill, both of, Pa. 769,660

Oct. 22. 1968 Division 01' Ser. No. 695,812.

()Ct. 31. 1967.1'at. \0.-3.525.323

June 29, 1971 The Reece Corporation Waltham, Mass.

WORKPIECE SENSOR AND TAPE CUTOFF FOR 348,113 8/1886 Diehli Primary EXaminer-H. Hampton Hunter Attorney-Linton & Linton ABSTRACT: The present machine is for affixing binding tapes to articles and including attachments for such machines which allow the machine to be run either manually or automatically. 1n the automatic position of the attachments, they start the machine, upon presentation of a workpiece to the machine, cut the tape at the start and finish of the work through a piston driven shear-type cutte-r having a driven blade cooperating with a fixed bar supporting the tape and stop the machine autbmatically. Also the operator can run the machine manually and stop the machine at any time when running the machine in said automatic position of the attachments.

PATENTED JUN29 I97\ SHEET 03 [1F INVENTORS 205527 A M/LLEE PATENTEU JUNZSIQYI 3.589.321

' saw on HF 12 PATENIEU .umzs lHTl SHEET 05 0F PATENTED June 9 I9?! SHEU 07 [1F FIG. 9

INVENTORS ROBERT F. MILLER nun BY ROY E. MILLER A TTO/QNE Y6 PATENIEnJummn 3,589,321

sum 03 0F 12 F/G..ZS.

INVENTORS 205527 F. MILLEe, 80v 5, MALL-6e PATENIEU JUN29 I971 SHEET 12 [1F ROY E.MHLLER WORKPIIECIE SENSOR AND TAPE CUTOFF FOR SEWING MACHINES DESCRIPTION The present application is a division from my copending application Ser. No. 695,8 l2, filed Oct. 31, 1967, now US. Pat. No. 3,425,373 dated Feb. 4, 1969, which is in turn a Continuation-ln-Part Application of Application Ser. No. 504,395 filed Oct. 24, 1965 and now abandoned.

The present invention is directed to an improvement-in tape applying machines and is more particularly concerned with machines for applying binding tape to articles and having means for severing the tape. a

It is the principal object of the present invention to provide a conventional sewing machine or adhesive tape applying machine with attachments which permit the machine to affix a binding tapeon articles, for example, canvas or leather shoe uppers, and which machine can be either manually or automatically operated and when automatically operated presentation of the article and binding to the machine will automatically start the machine, the binding tape will automatically be cut at the start and finish of the work, and the machine will be stopped after the cutting of the binding tape and before a second workpiece is presented to the machine.

A further and important object of the invention is to provide attachments for conventiohal sewing machines for attaching binding tape to a workpiece and which attachments sense the movement of the binding and workpiece during the sewing operation for automatically starting and running the sewing machine, cutting the biriding close to the leading edge of the workpiece, cutting the binding a second time close to the finish of the workpiece and stopping the operation of the sewing machine thereafter and yet which attachments permit the sewing machine to be manually operated for the starting and stopping thereof without the-binding cutting steps.

A still further object of the invention is to provide an attachment for conventional types of sewing machines for ap plying binding to articles 'and which attachment can be used to automatically start and stop the sewing machine before and after the sewing of each aiticle and severing the binding at the leading and trailing edges of the workpiece between the start ing and stopping of the sewing machine and which attachment further is long lasting, requiring little or no maintenance and reduces the ability required of the operator for such sewing machines while permitting an increase in production at less cost of the articles being sewn.

Further objects of the invention will be in part obvious and in part pointed out in the following description of the accompanying drawings in which;

FIG. 1 is a perspective view ofa sewing machine incorporating the present attachment.

FIG. 2 is an enlarged perspective view of the binding, sewing and cutting portion of the sewing machine as viewed from FIG. 1.

FIG. 3 is a further perspective view of the binding, sewing, and cutting portion of the sewing machine as viewed from the opposite side of FIG. 2.

FIG. 4 is a front elevation of the present sensing attachments for the sewing machine.

FIG. 5 is a top foreshortened view of the sensing andcutting attachment.

FIG. 6 is a side elevation partly in section of the sensing and cutting attachment.

FIG. 7 is a perspective view of a portion of the knife follower saddle forming a part of the sensing attachment.

FIG. 8 is an enlarged ex'ploded detailed perspective view of the elements of the sensing and cutting attachment.

FIG. 9a and 9b are diagrammatic showings of the pneumatic and electrical circuit for the present invention.

FIG. i0 is a perspective view of a sensor forming part of the present pneumatic circuit.

FIG. 11 is a top view of said sensor with interior details shown in dotted lines.

FIG. 12 is a cross-sectional view taken on line 12-12 of FIG. 10.

FIG. 13 is a cross-sectional view taken on lines 13-13 of FIG. 12.

FIG. 14 is a cross'sectional view taken of an electrically operated solenoid valve forming part of the present attachment.

FIG. 15 is a top view of a modified form of cutting and sensing attachment.

FIG. 16 is a side elevation partly in section of FIG. 15.

FIG. 17 is an end view ofthe top sensor element.

FIG. 18 is an end view of the bottom sensor element.

FIG. 19 is an enlarged exploded view of said modified form of cutting and sensing attachment.

FIG. 20 is an enlarged perspective view of the modified cutting and sensing attachment taken from the top of FIG. 15.

FIG. 21 is a partial end perspective view of FIG. 20 with the sensing elements removed.

FIG. 22 is a further enlarged top view of the sensor end portion ofFIG. 20 with the top sensor elements removed.

' FIG. 23 is a bottom perspective view of the cutting element of FIG. 20.

And FIG. 24 is an enlarged front view, partly broken away, ofthe knee switch.

FIG. 25 is an enlarged cross-sectional view taken on line 25-25 of FIG. 24.

Referring now more particularly to the accompanying drawings which include a conventional sewing machine by way of an example only for use with the present invention and wherein like and corresponding parts are designated by similar reference characters, numerals 1 and 2 indicate a pair of standards connected by a tie bar 3 upon which is pivotally supported a foot pedal 4 having an operating rod S'pivotally connected thereto at 6. A table top 7 is supported by said standards and supports a box 7a containing relays, sensor operated microswitches and indicators for the present attachment described more in detail hereinafter. A base 8 of a conventional sewing machine 9 is fixedly mounted on said table top, a box 711 is mounted beneath said table top and has an electrical lead-in cable from box 70 and feed cable 7d and contains an ofl on switch 7e and a manual-automatic switch 7f. Sewing machine 9 can be, for example, a model 47W sewing machine as produced by the Singer Company for use with the sensing and cutoff attachments shown in FIGS. 1-8 inclusive or a model 108 sewing machine for use with the sensing and cutoff attachments as shown in FIGS. 15 to 23. However, it is to be appreciated that the invention can be used with other types of sewing machines.

A knee-switch 73 as shown in FIG. 24 is attached to the bottom of table top 7 by screw 305 extending through plate 304. An arm 306 is attached to plate 304 as by welding and a clamp 307 consisting of two split rings fixedly joined together has arm 306 extending through one of said split rings and a rod 308 extending through the other split ring with screws 307a for tightening or loosening said split rings. A collar 309 has rod 308 extending therethrough and a setscrew 310 extending through and in threaded engagement with collar 309 for positioning said collar on rod 308. A coil spring 311 has rod 308 extending therethrough and one end bent around set screw 310. A knee plate 312 has tubular portions 313 and 313a through which extends rod 308 pivotally supporting said kneeplate. An end 311a of spring 311 extends alongside said kneeplate while said knee-plate has a stop 315 normally engaging screw 317 extending through and in threaded engagement with collar 316 retaining collar 316 on rod 308. A microswitch 318 is attached to rod 308 by screws 319 and has a plunger 314 to be operated at times by said knee-plate.

Said sewing machines have the conventional hand wheel 10 to which is attached an endless belt 11, a thread spool 12a and thread guide 12 and a sewing head 13 and base arm 14. Said head carries the conventional needle reciprocating arm 13a with needle 1312 alongside presser foot 13c above the feed dog 13d of the base arm 14. Operating rod 5 is connected to presser foot.13c by conventional means (not shown) for raising and lowering said presser foot. Said base arm also has pins mounted thereon for guiding the binding tape 16 from a supply thereof, not shown, towards said presser foot.

A combination brake and clutch unit 17 is fixedly supported beneath table top 7 and has an electric motor connected by wire 18 to a source of electrical current. Said brake and clutch unit is of the same type as shown in applicants copending ap plication Ser. No. 459,638, filed May 28, I965, now US Pat. No. 3,359,93l-Dec. 26, I967, and which clutch and brake unit has a driven pulley 17a around which extends endless belt 11 for starting, running and stopping said sewing machine.

Pipe 19 is connected to a source of air under pressure (not shown) and has a filter unit 20 and pressure regulator 21 interconnected therein and is connected by tube 24 to a port of a solenoid exhaust valve 22. A second port of said solenoid exhaust valve is connected to an oiler unit 23 by tube 155 and said oiler unit is connected by tube 156 to a port of solenoid brake valve 25, and to a port of solenoid drive valve 27.

The sensing and cutoff unit of the present attachment has a plate 28 which is fixedly attached to the sewing head 13 of the sewing machine 9 as best shown in FIG. 1 and which plate has a lateral finger 29 with a slot 30 therein. Three tubes 31, 33, and have nuts 32, 34 and 36 respectively fixedly attached to their ends while screws 37 extend through slot 30 to said nuts adjustably retaining said tube ends adjacent the bottom edge of said finger.

Plate 28 also has an opening 38 through which screw 39 extends into opening 55c in attaching block 55 in threaded engagement therewith.

Plate 28 further has opening 40 with clamp 41 being attached to said plate by a screw 43 extending through opening 42 in said clamp and opening 40 retained by washer 44 and nut 45.

A cylinder block 46 has opening 47 through which extends screw 49 through washer 48 into an opening (not shown) in flange 50 of attaching block in threaded engagement therewith. Said cylinder block further has an opening 51 with screw 53 extending through washer 52, opening 51 and open ing 54 of attaching block 55 in threaded engagement therewith.

Said attaching block has an opening 55a in which is positioned a semicircular sleeve 56 retained by screw 55h, provid' ing a bearing for the sliding therethrough of a conventional pressor foot control element (not shown).

Said cylinder block also has a back recess 57 in which is positioned guide bar against springs 58 and 59 while screws 63 and 64 pass through openings 61 and 62 in said guide bar and said springs into threaded openings in said cylinder block, see FIG. 6.

Said cylinder block 46 further has a bore 65 through which extends a piston rod 66. Piston rod 66 has a side recess 66a in which said guide bar is positioned and which provides cam 66b and a piston 67 upon the top of which is positioned a ring 68 with said piston and ring slidably mounted within the bore of cylinder 69 which is in threaded engagement with cylinder block 46 around bore 65. Cylinder 69 has a threaded opening 70 in which is positioned threaded end 72 of elbow 71 while a threaded nipple 73 is also in threaded engagement with said elbow.

Said piston rod further has a recessed end 74 with opening 75 therethrough while a knife blade 76 is positioned in said recess and a plate 77 is held against said knife blade by a screw 78 extending through opening 75 in threaded engagement therewith. Pins 76a extend through opening 76b in said piston rod, opening 760 in said knife blade and openings 76d in plate 77.

A bushing 79 is positioned on said piston rod below piston 67 while a spring 80 is mounted in bore 65 and pushes against said bushing 79 tending to move said piston rod upwardly drawing said knife blade 76 towards cylinder block 46.

A microswitch base 81 has a side opening 82 for receiving screw 83 and a second opening 84 for receiving a screw 85 which screws extend into support 86 and microswitch 87 for supporting the same in said base. A plunger 87a is slidably mounted in cylinder block 46, see FIG. 6, for being pushed by cam 66a of said piston rod when said piston rod reaches the end of its stroke to activate microswitch 87. A cover 88 for base 81 has recesses 89 and 91 for receiving screws and 92 which extend into openings 90a and 92a in said base 81 detachably retaining the cover thereon. Screws 94 extend through washers 93 and openings 94a in said microswitch base and into cylinder 46 as shown in FIG. 3 for attaching said microswitch to said cylinder block.

A cylinder cover 95 extends around the lower portion of the sewing machine base arm 14 as shown in FIGS. 2 and 3 with a bedcap 96 against disc 97 of said sewing machine base arm.

A throat plate 98 is mounted upon said bedcap. Said disc 97 has opening 99 while bedcap 96 has an opening 100 for receiving a screw 101 in threaded engagement therewith. Likewise bedcap 96 has opening 104 and disc 97 has opening 105 for receiving screw 106 in threaded engagement therewith retaining the same together. Openings 107 and 109 are provided in a sensor holding plate 112 for receiving screws 108 and 110 respectively while said sensor plate is inserted in opening 111 in said bedcap with screws 108 and 110 being in threaded engagement with openings 108a and 1100 respectively of disc 97. Tubes 113, 115 and 117 have nuts 114, 116 and 118 respectively fixedly connected thereto while screws 119 extend through slot 120 in sensor holding plate 112 each in threaded engagement with one of said nuts for adjustably supporting said tubes with their open ends below throat plate 98.

Said bedcap has a side recess 121 in which is positioned a knife cutting bar block 122 with screws 124 extending through openings 123 and screw 126 extending through opening of said knife cutting bar block into said bedcap retaining the supported flange 127 on top face 128 of said bedcap and above said throat plate 98. Bedcap 96 further has a top face 129 upon which is seated finger guard 130. A screw 131 extends through openings 132 in said finger plate into openings 132a of disc 97. Side 133 of said throat plate 98 extends below face 128 of said bedcap while side 133a is mounted upon end 129!) of said bedcap and has top openings 134 for the conventional feed dog of the sewing machine.

Plate 135 is attached to base arm 14 by screw 135a for retaining one side of cylinder cover 95 thereon.

A tap guide 136 is mounted upon the top of said cylinder arm and retained by screws 137 for twisting the binding tape 16 to a flat position beneath the presser foot 130. A second plate 138 is also mounted on said cylinder arm by screw 139 and thumb screw 140 for retaining the other end of said cylinder covering the said arm.

A nipple 73 is threadedly attached to elbow 71 and connected to tube 141 connected to air valve cutting solenoid 142, which has exhaust port 142a. A second nipple 143 is also connected to a second port of said solenoid cutting valve 142 and to a tube 144.

Wires 145 and 145a are connected to said solenoid cutting valve while wires 146 are connected to microswitch 87.

Tube 147 is connected to tube 144 and one port of a startstop microswitch sensor block 174 while tubes 35 and 117 are attached to other ports of said microswitch sensor block.

A tube 149 is also connected to tube 144 and one port of a second cut microswitch sensor block 150 while tubes 31 and 113 are attached to other ports of said second cut microswitch sensor block.

A tube 151 is also connected and to tube 144 to one port of a first cut microswitch sensor block 152 while tubes 33 and 115 are connected to other ports of said microswitch sensor block 152.

Said microswitch sensor blocks 174, 150 and 152 are more fully disclosed in FIGS. 10- 13 inclusive and will be described more in detail hereinafter.

A solenoid shut off valve 153 has tube 154 connected to one port thereof and also to tube 155 and a second port connected to tube 144. A tube 156 connects the lubricating cylinder 23 to one port of drive solenoid valve 27 and by a tube 157 to a port of brake solenoid valve 25. A second port of said brake solenoid valve 25 is connected by tube 159 to the brake operating port of the clutch and brake unit 17. A tube 16] connects a port of the drive solenoid valve 27 to the drive port of said brake and clutch unit 17 and includes a flow control valve 160. A tube 162 connects the exhaust port of said drive solenoid valve 27 to the exhaust port ofexhaust solenoid valve 22 and by tube 163 to a further port of the brake solenoid valve 25. Tube 164 connects tube 162 with the exhaust port of said brake and clutch unit 17.

Wire 165 is connected to the solenoid of shut off solenoid valve 153 as is a wire 166 which is also connected to wire 145. Wire 167 is connected to the exhaust solenoid valve 22 as is wire 168 which is also connected to wire 169 to brake solenoid valve 25 and to the drive solenoid valve 27. A wire 170 is connected to both said brake and drive solenoid valves 25 and 27 and to a wire 171. Also wire 172 is connected to wire 168.

The electrical connection posts for the drive motor of the clutch and brake unit 17 are indicated at 173.

The microswitch 87 of FIG. 9a is tied into FIG. 917 by dotted lines A, while sensor blocks 152, 150 and 174 of P16. 90 are tied into their microswitches ofthe same number in FIG. 9b by lines B, C, and D respectively. Likewise wires 167, 171. 172, 145, 145a, and 165 of FIG. 9a continue on FIG. 9b as E, F, G, H, l, and J, respectively.

The microswitch sensor blocks 174, 150 and 152 are similar and therefore, microswitch sensor block 174 is shown in FIGS. 13, as representative of all three. Said microswitch sensor block 174 has a bushing 175 extending therein and which bushing has adjusting stern 176 in threaded engagement therewith and extending therethrough into an air control seating disc 177 having a tapered opening providing a needle valve. Said disc is held within said sensor block by a cap 178 in threaded engagement with said block. A passageway 179 leads to one side of said seating disc 177 and to threaded ports 174a and 174b. A threaded port 1746 extends into said sensor block and connects with a passageway 180 adjacent said adjusting stem and also in communication with a lateral passageway 181 leading to recess 182 in said block. A diaphragm 183 extends across recess 182 and is held thereon by microswitch 148 while a plunger 184 is mounted on said diaphragm and positioned for operating said microswitch.

Tube 35 is connected to port 1740 while tube 147 is connected to port 174!) and tube 117 is connected to port 174: by being in threaded engagement therewith.

The amount of air to pass from passageway 179 to 180 is controlled by adjusting stem 176 relative to disc 177.

When the pressure within passageway 181 is relatively high as when a workpiece is between the ends oftubes 35 and 117 stopping the flow of air therefrom diaphragm 183 is moved upwardly operating microswitch 174. However, when the pressure below diaphragm 183 is lowered as when said workpiece passes from between the ends of tube 35 and 117 the diaphragm is lowered again operating microswitch 148.

The exhaust solenoid 22 is a conventional three-way solenoid valve such as are solenoid valves 142, 25 and 27 as produced by the Automatic Switch Company. An enlarged view of solenoid valve 22 is shown in cross section in FIG. 14 as an example of all three solenoid valves. Said valve has base 185 with a passageway 186 to which is connected tube 24 and a center passageway 187 connected to tube 155. A plunger 188 is slidably mounted in the bore of tube 189 surrounded by an electrically operated solenoid 190 connected to wires 167, and 168 and said plunger normally closes passageway 187. The bore of tube 189 further is connected to tube 162. Thus when air enters from tube 24 into passageway 186 and the solenoid is deenergized said air passes around plunger 188 through tubes 189 and 162 to the exhaust port of the clutch and brake unit 17. However, when solenoid 190 is energized it raises plunger 188 permitting the air to pass from passageway 186 to passageway 187 to tube 155.-

Solenoid valve 153 is a conventional two-way solenoid valve which can be obtained from the Automatic Switch Company and is similar to solenoid valve 22 except that it does not have the exhaust opening but a plunger such as 188 merely opens and closes two passageways similar to passageways 186 and 187 to pennit the connecting and disconnecting of tubes 144 and 154 by solenoid valve 153.

in the operation of the sewing machine with the present attachments connected thereto air under pressure is fed into tube 19 while electrical current is supplied to posts 173 for driving the clutch and brake unit and also to cable 7d. With the switch 7fin its manual position, that is connected to point 7i and switch 7e closed, current is sent through line E to the exhaust solenoid 22 supplying air to tube to tube 154 and to tube 156 and by tube 157 to solenoid brake valve 25 and also to solenoid drive valve 27. At the same time current is supplied to switch 73, but will proceed no further due to switch 7g being in its normally open position as shown in FIG. 9b. When the operator moves the knee lever controlling switch 73, said switch will be closed directing current through line F to the brake and drive solenoid valves 25 and 27 operating the same driving the sewing machine allowing the operator to perform a sewing operation without the automatic controls. That is the cutoffunit 69 will not cut the binding 16 since shut off valve 153 is in its closed position. Whenever the knee lever is released by the operator switch 73 will open stopping the sewing machine. Thus when solenoid valve 25 is deenergized air will pass from tube 157 to tube 159 to the brake port of the clutch and brake unit 17 stopping pulley 17a and thus sewing machine 9. However, when said solenoid valve 25 is energized then tube 157 is closed and air from tube 159 is exhausted through tubes 163 and 164 to the exhaust port of unit 17 leaving pulley 17a free.

When solenoid valve 27 is energized air passes from tube 157 therethrough to tube 161 and the drive port of unit 17 causing the rotation of pulley 17a running the sewing machine 9. However, when said solenoid valve 27 is deenergized air from tube 161 is exhausted through tube 162.

With switch 7 in its automatic position, that is connected to point 7h and switch 72 closed, current; is sent through line E to the exhaust solenoid 22 and through line J to the shutoff solenoid 153 controlling the air feed to the cutter 67 and sensors 01, 2 and 3. At the same time current will be supplied to the common lead K to the microswitch 87, and the microswitches of sensor blocks 152, 150 and 174 and thus lines B, C and D, as said microswitches will be closed as shown in FIG. 9b, when work is presented to the sewing machine. When there is no work in the sewing machine said common lead will be connected to the lower contacts of the microswitches 148 of sensor blocks 152, 150 and 174. The current from said common lead to microswitch 87 will feed through microswitch 87 back to the lefthand switch on relay 191. As relay 191 is not energized at this point the left-hand switch thereof will be open preventing the current from proceeding further in the circuit. The current passing through microswitch 152, when there is no work in the sewing machine, will pass from the common lead K through the lower contact of microswitch 152 to energize light 195'. At the same time the current is passing to the right-hand switch of relay 194, but since the switch is open the current will proceed no further. The current from common lead K to microswitch 150 will pass through the lower contact thereof to energize light 196 and at the same time goes to the left-hand switch of relay 193 which is open preventing the current from proceeding further. The current from switch 174 passes through the lower contact thereof to energize lamp 197'.

When a work piece such as a canvas or leather shoe upper is passed between tubes 35 and 117 an increase in pressure occurs in the microswitch sensor block 174 closing said microswitch as shown in FIG. 9b at which time the current is supplied from the common lead K on microswitch 148 of sensor block 174 through switch 7g which is in its closed position also as shown in FIG. 9b and goes from there to the brake and drive solenoids 25 and 27 driving the sewing machine. As long as the workpiece remains in the sewing machine microswitch 148 of sensor block 174 will remain closed and the sewing machine will continue to sew. Sensor block 174 includes microswitch 148 as does sensor blocks 150 and 152.

As the workpiece is moved to between tubes 33 and 115 the pressure in the microswitch sensor block 152 increases and said microswitch 148 of sensor block 152 will move to the position shown in FIG. 91) at which time current will be fed from the common lead K through said microswitch of sensor block 152 to the normally closed contact of the middle switch of relay 191 and through this middle switch to the cutting solenoid 142 which opens and admits air to the top of cylinder 80 moving the cutting knife 76 down to cut the binding 16. As the piston rod 66 approaches the end of its downward stroke cam 66d pushes plunger 87:: against microswitch 87 moving the same so that the common lead K will be joined to the lower contact of microswitch 87 sending current to the left-hand switch of relay 192 and therethrough to the coil of relay 191 energizing said coil. As the coil to relay 191 is energized it will move the three switches of relay 191 to the right and at this point the power connection through the middle switch of relay 191 to the cutting solenoid 142 will be broken deenergizing said cutting solenoid 142 releasing the air above piston 67 through exhaust port 1420 of the cutting solenoid 142 so that spring 80 returns the cutter 76 to its upper position. At the same time a holding circuit will be formed through the right hand switch of relay 191, to hold the coil of relay 191 energized. As the cutter 76 returns to its upper position the microswitch 87 will once again move to the position shown in FIG. 9b thereby sending current from the common lead K through the upper portion of microswitch 87 through the lefthand switch of relay 191 to the coil of relay 192 energizing the coil thereof, moving the switches of relay 192 to the right forming the holding circuit for the coil of relay 192 keeping it energized and holding its switches in their right-hand position.

As the workpiece is moved between tubes 31 and 113 air pressure increases in the microswitch sensor block 150 moving the microswitch thereof to its position shown in FIG. 9b and when the microswitch closes as shown, current will be sent from the common lead K to the coil of relay 193 moving the switches of relay 193 to the right and forming a holding circuit retaining the coil of relay 193 in an energized condition and the switches thereof in their right-hand position. The relays and their switches will remain in these positions during the sewing operation on the workpiece. Relay 191 thus cancels the current to the cutting solenoid 142 so that knife 76 does not make a second cut of the binding 16 until the workpiece leaves the tube 31 and 113.

As the workpiece is further moved clearing the sensing tubes 31 and 113, microswitch 148 of sensor block 174 will move to its lower position stopping the sewing machine. The microswitch of sensor block 152 will also move to its lower position at which time current will be supplied to the right hand switch of relay 194 but will proceed no further due to the fact that relay 194 is in its deenergized position. Light 195 will also be lighted. When the workpiece clears the sensor tubes 31 and 113 the microswitch of sensor block 150 will move to its lower position energizing lamp 196, but current will be fed through the left-hand switch of relay 193 which is in its righthand position and the current thus will pass through the middle switch of relay 194 back through the middle switch of relay 192 which is in its right-hand position, and back through the middle switch of relay 191 which is in its right-hand position, to cutting solenoid 142. The cutter blade 76 will then be caused to descend until it reaches the bottom of its stroke cutting binding 16 close to the finish f the workpiece and moving microswitch 87 so that the common lead K is connected to the lower contact of microswitch 87 feeding current through the left-hand switch of relay 192 which is in its right hand position, and to the coil ofrelay 194 energizing the same. moving its switches to the rightv When this occurs the current being fed to the cutting solenoid 142 will be broken by the middle switch of relay 194 permitting cutter blade 76 to return to its upper position. At the same time the return circuit for the coils of relays 191, 192 and 193 which goes through the left-hand switch of relay 194 will be broken thereby deenergizing each of these relays allowing their switches to move to their left-hand positions. Simultaneously with the return of the cutter blade 76 to its upper position, microswitch 87 again moves to its position as shown in FIG. 9b and the current from the common lead K goes to the open left-hand switch of relay 191.

When relay 194 was energized, a holding circuit was formed through the microswitch of sensor block 152 and the righthand switch of relay 194 to maintain the relay 194 in its energized position and with its switches in their right-hand position. Relay I94 remains energized between the introduction of workpieces to the sewing machine. When a further workpiece is fed to the sewing machine and as soon as the microswitch of sensor block 152 moves to its position as shown in FIG. 9b, the circuit to relay 194 is broken allowing the switches of relay 194 to move to their left-hand position and the operation of the sewing machine and attachments thereto will be the same as previously described for the first workpiece.

In the aforementioned description of the operation of the present apparatus reference to right, left, up or down for the elements refers to these directions on FIG. 9b.

Lamps I, 196, 197' and 198 are connected to cable 7d and lamp 195 is connected to the microswitch of sensor block 152, lamp 196' to the microswitch of sensor block 150, lamp 197' to the microswitch of sensor block 174 and lamp 198' to switch 7e. Thus, lights 195', 196' and 197 are only lit as long as there is no workpiece in the sewing machine and they will be turned off as soon as the microswitches of sensor blocks 152, and 174 are actuated. Further light 198 is always lit as long as the current is turned on to the sewing machine whether switch 7fis in the manual or automatic position.

FIGS. 1523 inclusive disclose a modified form of sensor and tape cutoff unit particularly for use with a model 108 sewing machine as produced by the Singer Company. Certain elements of this modified device are similar to those used in the device shown in FIG. 8 and have been given corresponding reference numerals.

Block is a conventional part of said sewing machine and a plate 196 is mounted on the top thereof having openings 197 in which are positioned tubular washers 198 above which are mounted rings 1980. A block 199 is mounted upon plate 196 and has openings 200 which match with openings 197 for receiving screws 201 therethrough into threaded engagement with block 195. Block 199 also has a recess 202 in one end and an inverted T'shaped groove 203 extending across the top thereof.

A plate 204 has a tongue 205 extending into recess 202 and having an opening 209 coinciding with opening 206 in plate 196 while a spring 207 extends into opening 209 and screw 208 extends through said spring and openings 209 and 206 into threaded engagement with block 195.

Bolt 210 has its head slidably positioned in recess 203 and extends through opening 211, washer 212 and has nut 213 thereon retaining arm 214 on block 199 with said arm extending laterally therefrom. Said arm further has a curved support 215 extending laterally of the same with a flat end 216 through which extends slots 217 for receiving screws 218 therethrough to engage openings 301 in cylinder block 279 for retaining said cylinder block on the right hand side of support 215. An L-shaped plate 219 is fastened to end 216 of support 215 by screws 222 which extend through washers 221, openings 220 in said L-shpaed plate and into threaded openings 223 in end 216. Support 215 has opening 224 against which is positioned the washer 225 and through which extends screw 226 into a threaded opening 303 in the cylinder block 279. I.-shaped plate 219 also has openings 227 which match with openings 22811 of a sensor arm 228 with screws (not shown) passing through openings 2280 into threaded engagement with openings 227. A spring 230 has an opening 229 for a screw (not shown) in threaded engagement with opening 231 in said sensor arm whereby said spring extends across slot 234. Said sensor arm also has slot 232 through which extends screws 233 into threaded openings in block 32, 34 and 36 fixedly connected to and supporting sensor tubes 31, 33, and 35 respectively.

A bed extension arm 235 has an end seated on recess 2350 in the bottom of arm 214 and has openings 236 with screws 238 extending through washers 237 and said openings 236 into threaded openings (not shown) in recess 235a whereby said bar extends beneath support 215. Said bar also has a lateral groove 239 in the opposite end thereof together with a flat top face 240. A knife cutting bar 241 has key 242 seated in recess 239 and a longitudinal recess 243. A knife follower 244 is mounted upon face 240 of bar 235 below recess 243 and has a slanting edge 245 extending into said recess 243. Knife cutting bar 241 also has a threaded opening 247 in alignment with opening 246 in said arm 235 while a screw 249 extends through washer 248 and opening 246 into threaded engagement'with opening 247.

Said knife follower 244 has an elongated opening 250 in alignment with threaded opening 251 in said arm 235. A curved spring 244a has a slotted opening 244): in alignment with the opening 251 on the bottom of arm 235 and with its free end 244C adapted to lie on the surface 240 of arm 235 against the edge of knife follower 244 opposite the edge 245. A screw 253 extends through washer 252, opening 244b, threaded opening 251 and into slotted opening 250. Thus spring 244a will urge the knife follower 244 into engagement with the far edge of recess 243 and the knife follower 244 will be free to move on the end of screw 253 against the action of spring 2440 when the knife descends. A pressor foot 254 is shown for use with the present device and has an opening 255 for receiving a screw for attachment to the conventional pressor foot lifting rod (not shown) of the sewing machine.

A second sensor support 256 has an elongated slot 257 in which are positioned the nuts 258 fixedly attached to the sensor tubes 113, 115, and 117 with said nuts retained in slot 257 by screws 259 in threaded engagement with openings 260 and against nuts 258 whereby tubes 113, 115 and 117 can be adjustably aligned with tubes 31, 33, and 35 respectively. Said sensor support 256 also has an opening 261 through which extends a screw 262 into threaded opening 2620 of bar 235. A throat plate 263 has a recess 263a receiving the tongue 204a of plate 204 and also an opening 264 having a screw extending into a conventional threaded opening (not shown) in the end ofthe arm 14 ofthe sewing machine.

Support 215 has threaded openings 265 matched with openings 267 in a plate 266 with screws 268 extending through the openings 267 into threaded engagement with openings 265. Plate 266 also has openings 269 through which extends screw 270 into the threaded openings (not shown) in the bottom of the solenoid valve 271 in threaded engagement therewith. Said solenoid valve also has a threaded opening 272 with nipple 273 therein and connected to a pipe coupling 273a connecting the same to tube 144. A second nipple 274 is connected to the opposite side of said solenoid valve and also to a pipe coupling 275 for being joined to tube 141. A cover 276 is mounted upon the end of said solenoid valve and has exhaust opening 142a for said solenoid opening thercthrough.

Tube 141 is also fastened by coupling 277 to nipple 278 joined to cylinder 69 having piston ring 68 and piston 67 slidably mounted therein. Said piston has ring 79, spring 80 and cutting blade 76 as described in the form as shown in FlG. 8 with piston rod 66 extending into bore 280 in the cylinder block 279 while cylinder 69 is in threaded engagement with thread 281 of said cylinder block. Said cylinder block has openings 282. a rear recess 283 with springs 284 and block 285 mounted in said recess against the recess 66a in piston rod 66 and retaining in position by screws 287 extending through openings 286 and springs 284 into threaded openings 282. Plunger 87a is slidably mounted in said piston block as best shown in FIG. 16 for being moved by cam 66b of said piston rod.

A microswitch supporting block 288 has a recess 289. A cover 290 for said microswitch block has recesses 292 for receiving screws 291 which extend into openings 298 of said block and retaining said cover thereon. Said block further has openings 293 into which extend screws 294 into threaded openings (not shown) in the rear of said cylinder for retaining the same together. Microswitch 295 is positioned in block recess 289 and has openings 296 and 297 while screws 299 extend through openings 300 of block 288 and openings 296 and 297 of said microswitch retaining the same together. A spring 302 having a spring arm 303 is positioned between the contact of the microswitch and plunger 87a for activating said microswitch when said plunger is moved.

The operation of the sensor and cutting element of FIGS. 15l9 inclusive is substantially the same as described for the modification shown in FIGS. 4 to 8 inclusive. That is the sensor tubes 31, 33 and 35 are adjustably positioned relative to tubes 113, 115 and 117 for sensing the passages of the workpiece therebetween and operating the present system shown in FIGS. 90 and 9b so that when air is passed to tube 141 piston rod 66 is lowered against spring and the knife blade 76 cooperates with the knife cutting bar 241 and knife follower 244 severs the binding tape 16 thereon and at the same time cam 66!) operates plunger 87a and thus microswitch 295 in a similar manner to that previously described. Likewise solenoid valve 271 functions in the same manner as solenoid valve 142.

Knee-switch 7g is normally open in that spring 311 by its end 311a tends to pivot knee-plate 312 away from microswitch plunger 314 and stop 315 against screw 317. However, the operator can by using a knee push knee-plate 312 against plunger 314 closing microswitch 318 when desired.

Sensing tubes 31, 33 and 35 can be omitted without changing operation as they mainly blow lint away.

The present invention is capable of considerable modification and such changes thereto as come within the scope of the appended claims are deemed to be a part of the invention.

We claim:

1. In a sewing machine having a sewing head and a base arm, means for severing a binding tape being sewn on said base arm comprising a plate connected to said sewing machine head and positioned to one side of the path of movement of the tape through said sewing machine, a cylinder mounted on said plate, means for supplying air under pressure to said cylinder as required, a piston slidably mounted in said cylinder, a knife blade connected to said piston, said cylinder being positioned to one side of the path of movement of the tape and disposed at an angle such that when said piston is in its inward position in the cylinder the knife blade will be positioned to one side of the path of movement of the tape and when said piston is moved outwardly in said cylinder said knife blade will pass through the path of movement of said tape, a knife bar connected to said sewing machine base arm for supporting said tape, said knife bar being positioned such that said knife blade passes in sliding engagement therewith during its movement in the tape cutting direction whereby said knife blade and said knife bar cooperate to provide a shearing action for severing said tape.

2. Means mountable on a base arm of a sewing machine for severing tape comprising an extension arm mountable on the sewing machine base arm, a substantially U-shaped support having one leg thereto mountable on said base arm, a cylinder mounted on the other end of said support to one side of the path of movement of said tape and extending towards said extension arm, a piston slidable in said cylinder, means for supplying air under pressure to said cylinder as desired, a knife blade connected to said piston, resilient means tending to retain said piston inwardly of said cylinder and a knife cutting bar connected to said extension arm :for supporting said tape, said knife cutting bar being positioned such that said knife blade passes in sliding engagement therewith during its movement under the influence of air in the cylinder in the tape cutting direction whereby said knife blade and said knife cutting bar cooperate to provide a shearing action for severing said tape. 

1. In a sewing machine having a sewing head and a base arm, means for severing a binding tape being sewn on said base arm comprising a plate connected to said sewing machine head and positioned to one side of the path of movement of the tape through said sewing machine, a cylinder mounted on said plate, means for supplying air under pressure to said cylinder as required, a piston slidably mounted in said cylinder, a knife blade connected to said piston, said cylinder being positioned to one side of the path of movement of the tape and disposed at an angle such that when said piston is in its inward position in the cylinder the knife blade will be positioned to one side of the path of movement of the tape and when said piston is moved outwardly in said cylinder said knife blade will pass through the path of movement of said tape, a knife bar connected to said sewing machine base arm for supporting said tape, said knife bar being positioned such that said knife blade passes in sliding engagement therewith during its movement in the tape cutting direction whereby said knife blade and said knife bar cooperate to provide a shearing action for severing said tape.
 2. Means mountable on a base arm of a sewing machine for severing tape comprising an extension arm mountable on the sewing machine base arm, a substantially U-shaped support having one leg thereto mountable on said base arm, a cylinder mounted on the other end of said support to one side of the path of movement of said tape and extending towards said extension arm, a piston slidable in said cylinder, means for supplying air under pressure to said cylinder as desired, a knife blade connected to said piston, resilient means tending to retain said piston inwardly of said cylinder and a knife cutting bar connected to said extension arm for supporting said tape, said knife cutting bar being positioned such that said knife blade passes in sliding engagement therewith during its movement under the influence of air in the cylinder in the tape cutting direction whereby said knife blade and said knife cutting bar cooperate to provide a shearing action for severing said tape. 